1. Field of the Invention
The present invention relates to a binding for cross-country skis.
More precisely, it is related to a binding adapted to retain a boot whose tip is provided with a transverse journal axle, on the ski.
2. Discussion of Background and Relevant Information
The type of binding to which the present invention is directed includes a mounting plate fixed on the ski, as well as a pair of jaws adapted to stretch and retain between them, the transverse axle provided on the tip of the boot; one of these jaws, called a fixed jaw, is affixed to the mounting plate, whereas the other jaw, called movable jaw, may be displaced axially on the ski, this binding including a knuckle joint latching system.
This system comprises, on the one hand, a lever for opening and closing the binding, which is journalled around a transverse axis affixed to the movable jaw, and on the other hand, a toggle link journalled on the lever, and taking support on the mounting plate.
A binding of this type is described in the document FR-A-2,638,974.
In a preferred embodiment of the binding, the toggle link is an elastic mount, which happens to be a wire spring stirrup that takes the general shape of a "U" in an elevational view.
The binding that has just been described is generally satisfactory to skiers practicing cross-country skiing, insofar as performance and ease of use is concerned.
The pivoting of the tip of the boot, when walking on skis, occurs against the resistance of an elastic pad mounted in the binding, and supported against the frontal portion, or nose, of the tip of the boot.
During closing on of the binding, which is done by deformation of the knuckle joint, this joint crosses an over-center line while the elastic mount deforms temporarily; after crossing the over-center line, the jaws are closed, and practically all risks of involuntary opening of the binding are eliminated.
Deliberate opening of the bindings is done by lifting the opening lever, which brings about deformation of the knuckle joint in the opposite direction, and distancing of the movable jaw with respect to the fixed jaw, thus resulting in the release of the journal axis of the boot.
In some conditions in which these bindings are used, difficulties related to the presence of a certain thickness of snow between the two jaws have been encountered.
This wedge of snow, whose thickness adds to the diameter of the journal axis of the boot, stops the movable jaw from being displaced normally, so much so that it is no longer possible to correctly activate the knuckle joint mechanism for closing the binding. In order to try and do this the skier risks exercising excessive pressure on the opening lever, and this may result in the deterioration of the binding.